FIG. 21 of the accompanying drawings schematically illustrates an example of stylus type profile meter of the conventional art. In FIG. 21, A denotes a probe fitted to one of the opposite ends of a support member C that is placed on a fulcrum B so as to be able to swing on the latter. The fulcrum B is put on a fulcrum receiving recess. A displacement sensor D is arranged near the other end of the support member C in order to detect the vertical displacement of the probe A. The displacement sensor D is formed by using a differential transformer that generates an electric signal according to the vertical displacement of the probe A. At the same time, a probe pressure generator E for applying pressure to the probe A is arranged at the other end of the support member C. The probe pressure generator E has a coil F and a core G of a high magnetic permeability material arranged at a position shifted in the axial direction from the center of the coil F to press the probe A against the sample by the force that is generated according to the magnitude of the electric current flowing through the coil F to pull the core G of the high magnetic permeability material toward the center of the coil F. The probe A traces the surface of the sample as either the sample or the detection system thereof as shown in FIG. 1 of the accompanying drawings is driven to scan and minutely turns around the fixed fulcrum B according to the surface profile. Then, the displacement of the probe A is detected by the differential transformer D to observe and measure a surface step of the sample.
When measuring a soft sample by means of such a stylus type profile meter, the measurement time is required to be reduced in order to reduce the film thickness examination time. Then a high scanning speed is required while the force pressing the probe down needs to be reduced in order to prevent the sample from being deformed and/or damaged. However, when the sample is scanned at high speed by small force, the probe can jump up at a rising step as shown in FIG. 1 to make it impossible to accurately measure the step.
FIG. 2 of the accompanying drawings schematically illustrates an example of a jump of a probe. After jumping up into air at a step on a substrate, which is a sample, the probe oscillates for a number of times on the surface of the sample. The graph of FIG. 2 is obtained by measurement when the probe pressure was generated by a force of 0.15 mgf and the scanning speed of the probe was 0.1 mm/s. The sample was the same as the one illustrated in FIG. 1. In FIG. 2, the horizontal axis indicates time and the scanning operation started at time 60 ms and proceeded by 70 μm at time 760 ms. The resist film had an end, or a step, at position that corresponds to 380 ms and the displacement rose there so that the probe jumped up there. Then, the probe fell back but jumped up again on the surface of the resist film to oscillate repeatedly. The height of jump of the probe depends on the moment of inertia around the fulcrum and “the distance between the fulcrum and the probe” beside the above conditions (see, for example, Patent Document 1).
The inventor of the invention of the present patent application proposed to increase the force pressing down the probe in order to reduce the jump of the probe after detecting the jumps as a method for dissolving the jump problem of a probe (see Patent Document 1). With such a method, it is necessary to wait until the jumps of the probe (or oscillations of a plurality of times) subside, keeping the force being exerted to the probe to a raised level, and then reduce the force gradually to the original level. With this technique, the sample is subjected to large force for a certain period of time. Therefore, while the jumps of the probe are reduced, the sample is disadvantageously subjected to large force even for a short period of time.    Patent Document 1: JP-A-2006-226964